KR20050101350A - Electrochemical energy source and electronic device incorporating such an energy source - Google Patents

Abstract

The invention relates to an electrochemical energy source comprising at least one fuel cell, which fuel cell comprises: a first current collector coupled to a negative electrode, a fuel source connected to said negative electrode, a second current collector coupled to a positive electrode, an oxidant source connected to said positive electrode, and an ion-conducting electrolyte located between said negative electrode and said positive electrode. The invention also relates to an electronic device incorporating such an electrochemical energy source.

Description

ELECTROCHEMICAL ENERGY SOURCE AND ELECTRONIC DEVICE INCORPORATING SUCH AN ENERGY SOURCE}

The present invention relates to an electrochemical energy source comprising at least one fuel cell, the fuel cell comprising: a first current collector coupled to a negative electrode, a fuel source coupled to the negative electrode, coupled to a positive electrode A second current collector, an oxidant source connected to the positive electrode, and an ion-conducting electrolyte located between the negative electrode and the positive electrode. The invention also relates to an electronic device comprising such an electrochemical energy source.

Electrochemical energy sources, including fuel cells, are known in the art. In principle, the fuel cell works like a battery. However, unlike batteries, fuel cells do not deteriorate or require electrical recharge (if fuel and oxidants are constantly added to the fuel cell). As long as fuel and oxidant are supplied to the fuel cell, the fuel cell will (in practical) produce energy in the form of electricity and heat. Compared with batteries, there are several advantages in using fuel cells. An important advantage of the fuel cell is that its capacity is much higher than that of conventional batteries. Moreover, fuel cells are a relatively clean energy source. Primarily, depending on the nature of the fuel used, only water vapor and carbon dioxide (when using a carbon containing fuel) are released during the electrochemical conversion process.

A conventional battery which is integrated into a part of a housing of an electrical appliance is disclosed in US patent publication US 5,180,645. Integrated batteries that are built (permanently) within, or form part of, the housing of the equipment have a number of advantages. Integrated batteries usually result in smaller overall sizes, lighter overall weight, and lower manufacturing costs of electronic devices. However, in addition to these advantages, known electrochemical energy sources formed integrally with part of the housing of the electronic device have several disadvantages. One of these drawbacks is that the degree of freedom in design is relatively limited, since the choice of the desired shape and / or type is extremely limited, i.e., only with a flat battery type and type. Thus, the form of the housing of the electronic device is generally adapted to the form and form of battery suitable for the particular device.

1 is a schematic diagram of the principle of operation for a fuel cell.

2 is an overall perspective view of an enclosure of an electrochemical energy source in accordance with the present invention.

3 is a perspective view of an electric shaver with an electrochemical energy source in accordance with the present invention.

It is an object of the present invention that an improved electricity comprising at least one fuel cell can be applied to an electronic device in which the energy source has any form, and thus does not lead to the disadvantages described above while maintaining the advantages of the prior art. To provide a chemical energy source.

This object is achieved by an electrochemical source which is described in the preamble and is characterized in that the electrochemical energy source has a curved and planar appearance. An important advantage of the electrochemical energy source with its curved and planar appearance is that the desired shape can be realized with respect to the electrochemical energy source, and thus the choice of shape and form with respect to the electrochemical energy source. The degree of freedom is much greater than that provided by the state of the art. The appearance of the electrochemical energy source can thus be adapted to the spatial limitations imposed on the electrical device in which the battery can be used, compared to the techniques known in the art. Thus, in terms of space, the electrical device can be more efficiently configured in many cases, due to more free choice of the appearance of the electrochemical energy source; This may save space in the device and allow more freedom in the design of the device. It is noted that the curved and planar appearance results in a curved battery having a curved and planar shape that may be concave / convex or wavy. However, it is also conceivable for those skilled in the art to apply an angular energy source having a ring shape.

In a preferred embodiment, the electrochemical energy source comprises a lamination of anode and cathode, the laminate having a curved shape to lie in one curved plane. Thus, relatively thin and long laminates can be provided in a relatively simple manner.

Preferably, the electrolyte is formed by a Proton Exchange Membrane (PEM). The PEM, a solid electrolyte, provides the transfer of protons from the negative electrode to the positive electrode. The operating temperature of the PEM is generally up to 120 ° C. Depending on the application of the fuel cell, different types of electrolytes may be used. In addition to the PEM, for example, alkali (AFC), phosphoric acid (PAFC), molten carbonate (MCFC), solid oxide (SOFC) and the like may be used as the electrolyte. In another preferred embodiment, the electrolyte is a liquid electrolyte, in particular alkali, phosphoric acid and dissolved carbonates held in a matrix located between the positive and negative electrodes. In addition, the matrix may vary regardless of the type of electrolyte used in the fuel cell. As for alkali, asbestos is generally used as a matrix, for phosphoric acid, silicon carbide is used, and for dissolved carbonate, a ceramic matrix of LiAlO ₂ is generally used.

In one preferred embodiment, the electrochemical energy source comprises at least one assembly of fuel cells electrically coupled together, wherein an insulator means is provided for isolating one cell in the assembly from another cell in the assembly. do. The fuel cells may be connected in parallel to increase the overall power output and / or in series to increase the voltage generated by the fuel cell.

In another preferred embodiment, cooling means for cooling the fuel cell is provided. The cooling means is suitable for controlling the heat generated by the fuel cell. The cooling means may be formed by, for example, a plate, a layer of flexible material, or a tube generally containing a cooling liquid.

Preferably, the electrochemical energy source comprises at least one battery electrically coupled to the fuel cell. The integration of fuel cells with batteries or supercapacitors creates a so-called hybrid system or hybrid energy source. The first advantage of the hybrid system is that high-load performance can be achieved. In situations where a relatively high power output should be produced, both the battery and the fuel cell may be implemented. Another advantage of the hybrid system is that by running the battery, the system can be easily started at relatively low temperatures. Unlike batteries, fuel cells generally function relatively slowly at low temperatures.

The positive electrode and the negative electrode are preferably provided with a catalyst for accelerating the electrochemical reaction in the fuel cell. The type of electrocatalyst generally depends on the electrolyte used. In the case of PEM or PAFC, platinum is mostly used as an electrocatalyst. In the case of AFC, a wide range of electrocatalysts are used, such as, for example, nickel, silver, metal oxides, spinels, noble metals, and mixtures thereof. It may be.

In a preferred embodiment, the fuel cell is laminated by a polymer deposited in a cavity formed in the positive electrode, the negative electrode, and the electrolyte. In this way, the fuel cell is formed by the so-called "Lithylene" technique. Such "Lithylene" technology is described in more detail in US Patent Publication US 6,432,576. In this technique, active material layers are not embedded in the polymer, but the polymer is used solely to bond the material layers together. The combination of positive and negative electrodes is generally important in fuel cells, as the operating temperature of the fuel cell can vary widely and thus significantly expand and contract the components of the fuel cell. Electrical contact in the solid state must be maintained between all components in the fuel cell at all temperatures. Polymer immobilization to all layers of the fuel cell may allow this solid state contact to be maintained between the catalyst layer and the electrolyte. The viscosity of the polymer should be low enough to fill the vacant space in the fuel cell so as to prevent leakage of the fuel. The "Lithylne" technique is particularly advantageous in the assembly of fuel cells ("stacks"), which allows the assembly to obtain relatively good mechanical strength by fixing the components of the assembly. Because it can. The polymeric material is formed to fit the shape of each hole (cavity), thereby fixing both the positive electrode, the negative electrode, and the electrolyte. The form of the assembly can be maintained in a relatively easy and simple manner by fixing the assembly. Despite the fact that the components are fixed by the polymer, it is important to maintain a sufficient supply of fuel and oxidant for each electrode.

The invention also relates to an electronic device comprising said electrochemical energy source. Advantageously, said electronic device comprises a housing comprising said electrochemical energy source. In the housing of the electrical device, the advantages of applying an electrochemical energy source having a planar and curved contour have already been described above.

The invention will be described in detail below with reference to the non-limiting embodiments illustrated in the drawings.

1 is a schematic diagram showing the principle of operation for the fuel cell 1. The fuel cell 1 comprises a positive electrode 2, a negative electrode 3, and a solid electrolyte 4 located between the positive electrode 2 and the negative electrode 3. In this particular embodiment, the (solid) electrolyte 4 is formed by a proton exchange membrane (PEM) and provides the transfer of protons from the negative electrode 3 to the positive electrode 2. The positive electrode 2 is connected to the oxidant source A and the excess oxidant and reactant outlet B, while the negative electrode 3 is connected to the fuel source C and the excess fuel outlet D. In this particular embodiment, hydrogen (in gaseous state) is used as fuel and oxygen (in air) is used as oxidant. The positive electrode 2 and the negative electrode 3 are electrically connected to the electronic device 5. In use, hydrogen will react with the negative electrode 3 to generate protons and electrons. Protons will be conducted to the positive electrode 2 through the PEM, and electrons will be transferred to the positive electrode 2 through the electronic device 5. In the positive electrode 3, oxygen will react with the protons and electrons received to form water as a reactant. The excess or unused small amounts of hydrogen and oxygen added to the fuel cell 1 may preferably be circulated and added back to the fuel cell via inlet A and inlet C, respectively. The positive electrode 2, the negative electrode 3, and the electrolyte 4 are formed in a polymeric material 9 that penetrates (fixes) these components 2, 3, 4 according to the "Lithylene" technique. By lamination. In this way, a mechanically stable fuel cell 1 can be produced. In this particular embodiment, hydrogen is used as fuel. In the fuel cell 1 shown, it is conceivable to use other types of fuel, for example methane or methanol. In addition to oxygen, other oxidants may also be used in fuel cells, for example hydrogen peroxide.

2 is a perspective view of an electrochemical energy source 6 according to the invention. The electrochemical energy source 6 comprises one or more, preferably stacked, fuel cells. 2 clearly shows that the electrochemical energy source 6 has a curved and planar shape (optionally selected).

3 is a perspective view of an electric shaver 7 equipped with an electrochemical energy source 8 according to the invention. The electrochemical energy source 8 has a curved shape so as to be optimally accommodated in the housing of the electric shaver 7. The appearance of the electrochemical energy source 8 may be chosen to meet the requirements imposed by the electrical device, for example the electric shaver 7, in this way the space available in the electrical device is It can be used to receive the electrochemical energy source 8.

As mentioned above, the present invention is used in an electrochemical energy source comprising at least one fuel cell.

Claims (11)

A first current collector coupled to the negative electrode, A fuel source connected to said negative electrode, A second current collector coupled to the positive electrode, An oxidant source connected to the positive electrode, and An electrochemical energy source comprising at least one fuel cell with an ion-conducting electrolyte located between the negative electrode and the positive electrode, The electrochemical energy source, characterized in that the electrochemical energy source has a curved and planar appearance. 2. The electrochemical energy source of claim 1, wherein the electrochemical energy source comprises a lamination of the positive and negative electrodes and has a curved shape such that the lamination is located in one plane. . The electrochemical energy source according to claim 1 or 2, wherein the electrolyte is formed by a proton exchange membrane (PEM). The electrochemical energy source according to claim 1 or 2, wherein the electrolyte is a liquid electrolyte held in a matrix positioned between the positive electrode and the negative electrode. 5. The assembly of claim 1, wherein the electrochemical energy source comprises at least one assembly of fuel cells that are all electrically coupled, wherein an insulator means connects one cell in the assembly. An electrochemical energy source, characterized in that it is provided to insulate from other cells within. Electrochemical energy source according to any of the preceding claims, characterized in that cooling means are provided for cooling the fuel cell. The electrochemical energy source of claim 1, wherein the electrochemical energy source comprises at least one battery electrically coupled to the fuel cell. The electrochemical energy source according to any one of claims 1 to 7, wherein the positive electrode and the negative electrode comprise a catalyst for accelerating an electrochemical reaction in the fuel cell. 9. The electrochemical method of claim 1, wherein the fuel cell is laminated by a polymer deposited in cavities formed in the positive electrode, the negative electrode, and the electrolyte. Energy source. Electronic device comprising an electrochemical energy source according to any of the preceding claims. The electronic device of claim 10, wherein the electronic device comprises a housing that includes the electrochemical energy source.